Empty markdown was correctly cached as empty html but then treated asoptimize-issues-avoid-noop-empty-cache-updates

if it was always out of date and always refreshed.

2 files changed, 23 insertions, 2 deletions

diff --git a/app/models/concerns/cache_markdown_field.rb b/app/models/concerns/cache_markdown_field.rb
index 98776eab424..a3a385825b7 100644
--- a/app/models/concerns/cache_markdown_field.rb
+++ b/app/models/concerns/cache_markdown_field.rb
@@ -85,8 +85,10 @@ module CacheMarkdownField
   def cached_html_up_to_date?(markdown_field)
     html_field = cached_markdown_fields.html_field(markdown_field)
 
-    cached = cached_html_for(markdown_field).present? && __send__(markdown_field).present? # rubocop:disable GitlabSecurity/PublicSend
-    return false unless cached
+    original = __send__(markdown_field) # rubocop:disable GitlabSecurity/PublicSend
+    cached  = cached_html_for(markdown_field)
+    return true if original.blank? && cached.blank?
+    return false unless original.present? && cached.present?
 
     markdown_changed = attribute_changed?(markdown_field) || false
     html_changed = attribute_changed?(html_field) || false
diff --git a/spec/models/concerns/cache_markdown_field_spec.rb b/spec/models/concerns/cache_markdown_field_spec.rb
index 129dfa07f15..12e568f2008 100644
--- a/spec/models/concerns/cache_markdown_field_spec.rb
+++ b/spec/models/concerns/cache_markdown_field_spec.rb
@@ -171,6 +171,25 @@ describe CacheMarkdownField do
       is_expected.to be_truthy
     end
 
+    it 'returns true if markdown and html are both empty' do
+      thing.foo = ''
+      thing.foo_html = ''
+
+      is_expected.to be_truthy
+    end
+
+    it 'returns false if markdown is empty but html is not' do
+      thing.foo = ''
+
+      is_expected.to be_falsey
+    end
+
+    it 'returns false if html is empty but markdown is not' do
+      thing.foo_html = ''
+
+      is_expected.to be_falsey
+    end
+
     it 'returns false if the markdown field is set but the html is not' do
       thing.foo_html = nil